# long in the tooth

> English word · Adjective

## Definitions
1. Old; aged.

## Etymology
Possibly from the practice of examining the length of horses’ teeth when estimating their ages: an old horse has long, rectangular incisors, and their occlusion angle is steep. Compare don't look a gift horse in the mouth.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-09-03.
Canonical page: https://plainspell.com/en/word/long-in-the-tooth